1. Field of the Invention
The present invention relates to a medical ligating apparatus for ligating living tissues by inserting the apparatus into a body in a trans-endoscopic manner.
2. Description of the Related Art
Conventionally, medical ligating apparatuses for ligating a lesion of a living tissue, such as polyp, by inserting the apparatuses through endoscope channels, and inserting them into cavities in a trans-endoscopic manner are known from Jpn. Pat. Appln. KOKAI Publication Nos. 10-194, 10-277046, 11-244294, 48-71090, 8-98840, and 54-30692 and the like. These medical ligating apparatuses are composed of: a sheath that can be inserted through an endoscope channel; a manipulating wire movably inserted through this sheath; a loop shaped ligating wire removably connected to a distal end of this manipulating wire; and a stopper provided at a proximal end of this ligating wire.
In this medical ligating apparatus, when a ligating wire is hooked on a lesion of a living tissue, such as polyp and a manipulating wire is pulled toward a proximal manipulating section side, a stopper moves relatively to the distal end side of the ligating wire. As a result, the loop of the ligating wire is reduced in diameter. Then, the lesion is tightly bound. A blood flow at the lesion is stopped by this ligation, and thus, the lesion tissue necroses and slips off several days later in a ligated state. Then, a ligating device consisting of the ligating wire and the stopper slips off at the same time, and is naturally discharged from the anus.
The ligating wire is formed of, for example, a synthetic resin such as nylon or polyolefin, or alternatively, stainless steel. The stopper is formed of a thin tube consisting of an elastic element such as silicon rubber. In addition, the stopper is a knot formed at a part of the ligating wire as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 48-71090.
After the ligating wire has been tightly bound on the lesion, it is required to isolate the ligating wire and manipulating wire connected to each other. Therefore, as disclosed in Jpn. Pat. Appln. KOKAI Publication No. 48-71090, a scissors is inserted through the endoscope channel, and a proximal end of the ligating wire is cut by the scissors. As disclosed in Jpn. Pat. Appln. KOKAI Publication No. 54-30692, a cutter member is provided at the distal end of a sheath, and a ligating wire is cut by the cutter member.
However, as described previously, after the ligating wire has been tightly bound on the lesion, the scissors is inserted through the endoscope channel in order to isolate the ligating wire and manipulating wire connected with each other. In a manipulation for cutting the proximal end of the ligating wire by the scissors, it is required to replace the medical ligating device with the scissors, and insert it into a body cavity in a trans-endoscopic manner. Thus, there is a problem that an operation time is extended.
In addition, with a structure in which an openable cutter member is provided in the distal end of the sheath as shown in FIG. 7 of Jpn. Pat. Appln. KOKAI Publication No. 54-30692, a large number of parts are required, resulting in higher manufacturing cost. In addition to wires of the ligating device, the manipulating wire for actuating the cutter member is inserted into the sheath. Thus, the sheath is increased in diameter, making it difficult to insert the sheath into an endoscope having a channel with its small internal diameter.
In the case of the cutter member in which a blade oriented in the transverse direction at a proximal end side as shown in FIG. 8 of Jpn. Pat. Appln. KOKAI Publication No. 54-30692 is provided in a cylindrically shaped member, there is a problem that its manufacture is very difficult, and the sheath is increased in diameter.
Further, in the conventional medical ligating apparatuses, the proximal end of the ligating wire is cut, thereby isolating the ligating wire and manipulating wire connected with each other. Thus, the ligating wire remains in the body cavity while this wire is extended from a ligating section. Therefore, for example, interference with another treatment device or endoscope may occur.